I too reckon that the song you want is not the familiar Blackleg Miner but instead the Jock Purdon composition titled Blackleg Mining Man, which, as Guest 999 says, can be accessed via the storming Whisky Priests performance in the link mentioned above.

BLACKLEG MINING MAN (Jock Purdon)

Who is that blackleg mining man? (x2) He's the one who helps the boss Nail his brothers to the cross; Who is that blackleg mining man?

Where was that blackleg mining man? (x2) He was nowhere to be seen When they killed young Jones and Green; Where was that blackleg mining man?

He was that blackleg mining man (x2) He was deep down in the mine, Gone through the picket line; He was that blackleg mining man.

Why does that blackleg mining man (x2) Dig the black black coal And put his marrers on the dole? Why does that blackleg mining man?

Someday that blackleg mining man (x2) Will rue what he has done When there's no work for his son; Someday that blackleg mining man.

One day that blackleg mining man (x2) Will realise he's sold his soul For a tub of blackleg coal; One day that blackleg mining man.>

He'll see that blackleg mining man (x2) When he looks into his glass – A traitor to his class; He'll see that blackleg mining man.

Who is that blackleg mining man? (x2) He's the one who helps the boss Nail his brothers to the cross; He is that blackleg mining man.